Latching device



June 24, 192,11. H. K. KRANTZ LATCHING DEVICE Filed July ll, 1940 F/GIZ/NVE/vro@ l A. KRA N TZ ATTQR/VEV Patented June 24, 1941 LATCHING DEVICEHubert K. Krantz, Rockville Centre, N. Y., assignor to Bell TelephoneLaboratories, Incorporated, New York, N. Y., a corporation of N ew YorkA@application .uly 11, 1940, Serial No. 344,891

(Cl. 7d- 532) 9 Claims.

This object is attained, in accordance with a feature of the invention,by pivotally mounting a centrally apertured -guard member on thefaceplate of the switching key and providing thereon an integral bolt orlatch which, when the key lever is moved to any of its switchingpositions,

is automatically moved in behind the lever shank to lock the lever inits operated position.

Another feature of the invention resides in a novel type of springbiasing arrangement for maintaining the guard in its latching position.

A' further feature of the invention is embodied in a finger-grip, formedintegrally with the guard, which facilitates the movement of the guardfrom its latching position.

These and other features of the invention will be readily understoodfrom the following dee tailed description made with reference to theaccompanying drawing, in which:

1 is a side elevation of the key-guard of this invention associated witha three-position lever type key, and shows the guard in its latchingposition;

Fig. 2 is a top view of the structure disclosed in Fig. 1;

Fig. 3 is a top view, corresponding to Fig. 2,

and illustrates the guard in its unlatching position;

Fig. 4 is an end view 'of the structure shown in Figs. 1 and 2; and

Fig. 5 is an end view of the structure shown in Fig. 3.

In the drawing, the key-guard I5 is shown mounted on the key face-plateEil by means of the shoulder pins I6 and.' i8, The shank of shoulder pinI5 passes through a circular hole at one end of the guard and is screwedinto, or otherwise permanently associated with the faceplate. The -guardis capable of pivotal movement about the pin IB. At its other end, the

guard is provided with a slot I l, which is slightly I;

arcuate. The shank of shoulder pin I8 passes through this slot and isxedly associated with the face-plate Ill. The extent to which the guardmay be pivotally moved about the pin I6 is limited bythe length of slotIl. To permit the movement of the guard by hand, a finger-piece 22 isintegrally formed on the guard and located near the slotted end thereof.The bosses 23, formed integrally with, and located on the under- 3 sideof the guard, provide bearing surfaces for the guard in its movementover the face-plate.

The :guard I5 may be stamped or otherwise formed of sheet metal. Asubstantial portion of the metal is removed from the center of the guardto furnish an aperture I9 through which a portion of the lever I2 andits handle supporting shank I3 protrude when the guard is in position onthe key structure. At the upper edge (viewing Figs. l and 2) of theaperture I9, the metal is turned up at right angles toform asubstantially semi-elliptical integral projection 2), midway of whosecurved edge there is formed an inwardly projecting bolt or latch 25. Atthe junction of the portion 2@ and the main portion of the guard l5, asmall aperture or slot 26 is provided, through which a humped portion 2of spring 28 protrudes. The spring 28 is located between the face-plateIt and the guard I5 and has one end partially encircling the shank ofshoulder pin i6, while the other end is terminated in a hook which ntsaround the shank of shoulder pin I8 and is free to move longitudinally,relative to the pin I8.

In Figs 1 and 2, the key lever has been actuated to one of its switchingpositions. Prior to such operation the key lever would occupy the normalposition illustrated in Fig. 3. In this position, the front edge oflatch 25 abuts the shank i3 of the lever, as clearly shown in Fig. 5,and the spring 28 is boweddue to the action of the back face ofprojection 2li on the spring hump 2l when the guard is caused to pivotabout the pin It.I During this action on the spring 28, the hooked endthereof moves from the position illustrated in Fig. 2 to that shown inFig. 3. Thus, when in the position shown in Fig. 3, the guard i5 isheld, under the tension of spring 28, with the edge of latch 25 abuttingthe lever shank i5. rWhen the lever is actuated to the right or leftfrom its mid-position, the lever shank i3 rides oli the latch 25 and,under the action of spring 23, the latch is snapped into position behindthe lever shank to effectively lock the lever in its actuated position.

In the event that the key must be operated from either of its actuatedpositions to its other actuated position, or to its mid-position, theguard is pivotally moved about the pin I6, the operator or attendantpushing on the iinger-grip 22 with one hand and grasping the knurledhandle I4 of the key with the other hand and moving it to the newposition. Pivotal movement of the guard removes the latch 25 from theoperating path of the lever shank I3, thus permitting unimpeded movementof the lever. When the lever is moved to its new position, the guard isreleased so that, under the action of spring 28, the latch snaps intoposition behind the lever, if the lever is now in one of its actuatedpositions, or into engagement with the lever shank I3, should the leverhave been moved to its mid-position.

The face-plate Ill is provided with a series of holes II through whichscrews or the like may be passed for engagement with the frame 33 whichsupports the key structure. It is to be `understood that the particularstructural details of the :key may be of any well-known design. vThe keywhich applicant has elected to disclose is of the well-known lever typein which an inverted U-shaped mounting bracket or frame 33 is used, andbetween the legs of which the circuit controlling springs are mounted.The bridge of the U-shaped bracket 33 is secured to the face-plate I .inany suitable manner and 1s provided'with two oppositely disposeddepending integral lugs 34 upon which the contact operating lever ispivotally mounted, the said lever carrying means for electricallybridging certain of the contact springs or for otherwise actuating theContact springs.

What is claimed is:

l. In combination, a switching key having an operating lever capable ofoccupying a mid-position and a plurality of alternate positions, asupporting member for said key, and a locking device comprising a guardpivotally supported on said supporting member and arranged to pivotabout one end between two eXtreme positions, means carried by said guard.and contacting said lever when said lever is in its mid-positionwhereby said guard is held in one of its extreme positions, and meanselective when said lever is moved to an alternate position to cause saidguard to automatically assume its other eXtreme position whereupon saidfirst-mentioned means locks said lever in its alternate position.

2. In combination, a switching key having an operating lever .capable ofoccupying a mid-position and a plurality of alternate positions, asupporting member for said key, and a locking device comprising a guardpivotally supported on said supporting member and arranged to pivotabout one end between two extreme positions, a latch carried by saidguard engaging said lever when said lever is in its Amid-positionwhereby said guard is held inone of its extreme positions, and vmeanseffective when said lever is moved to an alternate position for causingsaid guard to automatically assume its 'other eXtreme position whereuponsaid latch engages said lever in its alternate position and locks ittherein.

3. In combination, a switching key having an operating lever capable ofoccupying a mid-posi tion and a plurality of alternate positions, asupporting member for said key, and a locking device comprising a guardsupported on said supporting member and varranged to pivot about one endbetween two extreme positions, a latch carried by said guard engagingsaid lever when said lever is in its mid-position whereby said guard isheld in one of its extreme positions, and a spring effective when saidlever is moved to an alternate position for causing said guard toautomatically assume its other extreme position whereupon said latchengages said lever in its alternate position and locks it therein.

4. In combination, a switching key having an operating lever capable ofoccupying a mid-position and a plurality of alternate positions, asupporting member for said key, and a locking device comprising a guardsupported on said supporting member and arranged to pivot about one endbetween two extreme positions, a latch carried by said guard engagingsaid lever when said lever is in its mid-position whereby said guard isheld in one of its extreme positions, a spring effective when said leveris moved to an alternate position for causing said guard toautomatically assume its other extreme position whereupon said latchengages and locks said lever in its alternate position, and means formanually moving said guard so as to move said latch in disengagedrelation from said lever.

5. In combination, a switching key having an operating lever capable ofoccupying a midposition and a plurality of alternate positions, asupporting member for said key, and a locking device comprising a guardsupported by said supporting member and arranged to pivot .about one endybetween two extreme positions, a latch carried by said guard engagingsaid lever when said lever is in its mid-position whereby said guard is'held in one of its extreme positions, a spring elective when said leveris moved to an alternate position for `causing said guard toautomatically assume its other extreme position whereupon said latch ispositioned relative to said lever so as to lock said lever in itsalternate position, means for manually moving said guard so as to movesaid latch clear of said lever, and means comprising a slot in saidguard and a shoulder pin supported by said supporting member andoperating in the slot for dening the two extreme positions of saidguard.

6. In combination, a switching key having an operating lever capable ofoccupying a mid-posi tion and a plurality of alternate positions, asupporting member for said key, a face-,plate carried by said supportingmember and having a centrally located aperture through which saidoperating lever protrudes, and a locking device comprising a guardpivotally supported at one end on said falce-plate and having anaperture through which said lever protrudes, a latch integrally formedwith said guard and extending inwardly from the center of one of thedefining edges of the guard aperture and -located in the line of travelof said lever when said lever is in an alternate position, means forlimiting the pivotal movement of said guard comprising a shoulder pincarried on said face-.plate and a slot in the guard in which theshoulder pin functions, `an aperture in said guard in alignment withsaid latch, and means for maintaining said latch in the line of travelof said lever when said lever is in an alternate position, comprising aspring extending between the pivot support of said guard and saidshoulder pin and having a portion thereof projecting through saidlastmentionedt guard aperture and contacting said guard at a point in`alignment with said latch.

v'7. In combination, a multiposition switching key, a supporting frame,an operating member for said key journaled in the supporting frame andadapted to occupy a normal mid-position and a plurality of alternatepositions, and means for locking the operating member in any of itsalternate positions comprising a pivotally mounted guard member havingan aperture through which the operating member protrudes, a latchintegrally formed with said/guard and abutting said operating memberwhen the latter is in its mid-position, and means effective when saidoperating member is moved to any of its alternate positions for lcausingsaid guard latch to be moved into a position behind the operating memberto effectively lock the operating member in its alternate position.

8. In combination, a multiposition switching key, a supporting frame, anoperating member for said key journaled in the supporting frame andadapted to occupy a normal mid-position and a plurality of alternatepositions, and means for locking the operating member in any o-f itsalternate positions comprising a guard having a centrally locatedaperture, means for pivotally supporting said guard at one end in aposition such that the operating member protrudes though the aperture,means comprising a slot in one end of said guard and a cooperating pinwhich limits the extent of the pivotal movement of the guard about itspivot support, a latch carried by said guard and adapted to abut theoperating member when the operating member is in its mid-position, andmeans comprising a spring carried 'by said pin and said pivot supportand arranged to hol-d said latch and said operating member in abuttingrelation when the operating member is in its mid-position and to forcesaid latch into a position corresponding to the mid-position of saidoperating member when said operating member is moved to an alternateposition.

9. In combination, a multiposition switching key having an operatingmember, a mounting` plate for said key, a face-plate secured to saidmounting plate and having an aperture through which said operatingmember protrudes, and means for locking the operating member in anoperated position, comprising a guard member mounted on and insuperposed relation to said face-plate and having an aperture insubstantial alignment with the face-plate aperture, a shoulder pin forpivotally supporting one end of said guard on said face-plate, a secondshoulder pin cooperating with a slot in the other end of said lguard inlimiting the pivotal movement of said guard about its pivot support, alatch integrally formed with said guard and occupying a position in theline of travel of said operating member when said operating member is inan operated position, and means comprising a iinger-grip integrallyformed on said guard at the slotted end thereof for facilitating themanual movement of said guard and to remove the latch from the line oftravel of said operating member, whereby said operating member may bemoved to another operated position.y

HUBERT K. KRANTZ.

